 In an effort to enhance the efficiency and profitability of catfish production, researchers at Auburn University have developed an aquaculture system that incorporates flowing water raceways within existing ponds. We're here this morning talking about a technology that we're developing here, both at Auburn and also in collaborator farms around the United States, primarily in the southeast. We call it in-pond raceways where we take traditional ponds and we apply some new machinery if you will in such ways where we can gain greater levels of efficiency and hence productivity and profitability over traditional management systems. And so where we are here at Auburn this morning, we're on our upper fisheries experiment station where we have a number of units deployed in one of our upland ponds here. These systems are going to be a major part of the future of aquaculture in the United States so that we can be competitive in the world. The researchers are working on two versions of the in-pond raceways. One system is built into the pond itself and sits on a concrete pad and the other actually floats within the pond. The original on-farm prototype consists of a 40 by 100 foot concrete pad divided into six raceways that are 16 feet wide and 30 feet long. The walls between the raceways are 5 feet tall and metal walkways have been placed across both the head and tail ends for easy access. Smooth mesh-covered gates at each end keep the fish from escaping into the pond. The last 10 feet of the raceways are designed to serve as a quiescent zone or settling area for waste solids. In the original design, a small trough extending across the unit was built into the bottom of each raceway that had a cover that could open and close. The idea was that solids traveling along the bottom would fall into the trough. At preset intervals, the lid on the trough would close and a suction pump connected to the end of the trough could pull the water and solids out of the pond. The slurry would be stored in a holding tank where it could be dewatered and applied to a terrestrial crop as fertilizer. In later designs, the trough was eliminated and replaced by a 24-inch high knee wall to assist in solids settling and removal. Removing waste solids generated from fish in the system significantly reduces the amount of waste that needs to be processed by the remaining pond volume and allows for higher feeding rates and greater production efficiency. Originally, the water movement through the systems was provided by large paddle wheels placed at the front of the raceway. These paddle wheels had six panels that measured 4 feet by 8 feet, turning at 1 rpm, driven by one half-horse-drive motors. They could exchange all of the water in the raceways every 4 to 5 minutes. In addition to the paddle wheels, high-volume low-pressure blowers were installed to maintain adequate, dissolved oxygen during the nighttime hours. Floors are moving away from these types of paddles because they are more costly to maintain and only served a single function. The paddle wheels have now been replaced by what are called whitewater airlifts. The airlifts are constructed of three major parts, a blower, special diffuser hose formed into a grid, and a deflector hood that directs the water flow. The blower supplies air through the manifold to the diffuser grid which creates bubbles. The bubbles rise, hit the deflector hood, and the air and water mix is directed forward through the length of the raceway cell. The benefit of using the airlift is that it performs two functions. It moves the water through the units and adds oxygen at the same time. The blowers are very efficient and can run on very little energy. Because the airlifts operate 24 hours a day, a reliable source of power is a critical element and an auto starting generator is required. Energy requirement is constant, but it's relatively low in terms of the horsepower required. We actually use less energy per unit produced in this type apparatus than we do using open pond or traditional pond technologies. We produce a lot more fish, typically about three times the amount of fish using raceway technologies compared to traditionally managed ponds. But because we produce more fish, we also use more energy, but the energy used per unit is significantly less. In fact, almost half the amount of energy is required when we use raceway technologies as opposed to the traditional pond management. The raceways are situated along the side of the pond and a long baffle is placed down the center of the pond. This baffle, made of thin plastic, forces the water to travel around the entire pond before re-entering the raceway. Additional airlifts can be added in the corners of the pond to assist with the circulation and the mixing of the pond water facilitates the waste assimilation. The airlifts bring water from the lower levels to the top, ensuring that all of the algae are exposed to the sun. This enhances oxygen production and ensures that the whole volume of pond water can be used in the waste reduction. It takes about four to five acre feet of water to support each raceway. This pond is six surface acres and is five to eight feet deep, supplying about 36 acre feet of water for the six raceways. The second type of impond raceway conceived by Auburn is the floating raceway. It operates in a similar manner to the fixed raceways, but does not require draining the pond during construction or any pond alterations. They can be placed in the pond by a boom truck or launched from a trailer, like those used to carry a pontoon boat. The prototypes in place at several commercial catfish farms are five feet deep, with one foot of freeboard, 16 feet wide, and 40 feet long. Looking at the raceway out of the water, you can get an idea of its size. The structure above the man's head is an expanded aluminum walkway. The floating design uses a plastic membrane stretched over an aluminum or PVC coated wire mesh frame. This provides good structural rigidity and light weight. Once placed in the pond, the floats integrated under the walkway keep the raceway at the right level. The whitewater airlift features a 1.5 horsepower blower connected to a three-inch PVC air manifold running around the base of the unit. Multiple diffuser hose sections extend 42 inches across the opening of the manifold. The fish confinement gates are made from PVC coated, galvanized steel mesh. The floor is corrosion resistant rolled sheet aluminum. Having multiple raceway cells allows the farmer's greater inventory control than is possible in open pond culture. The systems that we're demonstrating here with the raceways allow us to have a known inventory of a single cohort, a single size group. And when we put them in, we put in 6,000 or 60,000. If one of them dies, we see it. And because we can put a bird net over the top of this kind of system very cheaply, we don't have to worry at all about bird predation on these animals. Likewise, when we're putting in a single size cohort, we completely eliminate the receivers or the one fish eating another opportunity that is very prominent in mixed batch or multi-batch systems in traditional open pond systems. Multiple raceways also allow the farmer flexibility to grow several sizes or species concurrently. By staggering the size classes, it is possible to have numerous annual harvests which provide good cash flow and reduce risk. There are two types of risk with the impond raceway system. The first deals with the electricity that powers the air pumps. Air pumps are the heart of the system flowing the air through the water and creating the current, getting the oxygen through the fish and the system. If this electricity should cease, then we have a real problem because a fish will not survive very long without this electricity and airflow. We have a backup generator which is a necessary part of the system to reduce this risk. The second risk are the waste and the uneaten feed that flow through the system into the pond environment which needs to clean up the water before it flows through a second time. To reduce this risk, we use a staggered production system where we put small fish in one cell, medium fish and large fish, and together that combined weight of fish will be less than what the pond environment can handle by handling it, I mean oxidizing the waste so that the water is clean for the next pass through. So we can reduce risk two ways, backup generator and also staggering our production and never having all the fish biomass at one time. The raceways are started with one quarter pound fish called stockers at a rate of four to seven fish per cubic foot. The target harvest weight for these fish is about two pounds. It is also possible to split one of the raceways into two sections where these smaller stockers can be produced. Small four to six inch fingerlings are stocked into this section at twenty to fifty fish per cubic foot. Having stockers on hand and easily accessible increases production efficiency because the next crop of fish is already on site. As you can see these animals are pretty aggressive on feed in these raceways. You can also probably notice the dark color. They are particularly dark in color, a really really beautiful fish in this kind of confinement setup. Not very much feed if any escaped this system. If you might notice on the downstream end we have a little bit of a feed skirt there where it retains the feed particles. We use a floating extruded pellet that animals are very able to get before it tries to escape the system. The main ingredients in catfish feed are soybeans, corn, wheat and a vitamin and mineral package. Feed conversion in raceways is generally better than in open ponds. The traditional systems management today gets somewhere in let's say two to one feed conversion ratio feed to fish flesh gained to maybe as much as two point five to one or worse. Whereas in the raceway work that we have done so far we are looking at numbers that are down around one point five to one or maybe even one point three to one in most of our trials. Even the fish confined to one area also makes it easier and less expensive to treat the fish if they get sick. When a group of fish reaches market size they can be harvested by just a few people. Crowding bars are placed into the raceway. The crowding bars are used to concentrate the fish so they can be scooped up with a basket suspended from a boom truck. The fish are loaded onto the truck which has several water tanks each supplied with oxygen and the fish are then transported to the processing plant. Production in the fixed and floating raceways has been in the range of ten to fifteen pounds of fish per cubic foot of raceway volume. This equates to twenty to twenty five thousand pounds per acre per year. In addition to the fish produced in the raceway, other filter feeding fish like tilapia and paddlefish can be grown in the rest of the pond. Using both the fish in the raceways and the fish in the open pond it is possible to produce twenty five thousand pounds per acre or more. Designs for the raceway are evolving as more producers adopt this technology. Many will modify the systems with hopes of improving their efficiency and reducing the cost of producing fish. The latest on-farm designs use pond levies as the baffle around which the water must circulate. This design incorporates ideas from both in pond raceway and split pond technologies. The farmers are trying to minimize the costs associated with retrofitting ponds to take advantage of this technology. One two-cell unit uses a plastic membrane draped over a fence to form the walls and floor of the raceway. A wooden walkway along the top of the posts gives the farmer access. The raceways are sixteen feet wide, eighty feet long and four feet deep and cost considerably less to construct than the concrete versions. The farmer expects that this twenty five thousand dollar investment will yield one hundred and twenty five to one hundred and forty thousand pounds of fish per year and can be paid for within two years. So as you can see after looking at these images and video we're talking about advancing the technology from traditionally managed aquaculture ponds to more mechanized production where we can be more competitive and stay competitive as we go forward. We are not just talking about producing more fish. We can produce more fish just by adding acreage but we are producing more fish a great deal more efficiently rather than doing the same old way, getting the same old result.